Neural stimulation lead fixation

ABSTRACT

An implantable lead having at least one electrode contact at or near its distal end prevents undesirable movement of the electrode contact from its initial implant location. One embodiment relates to a spinal cord stimulation (SCS) lead. A first injectable material is injected into the dura space to mechanically position the electrode array with respect to the spinal cord. Conjunctively for use with adhesives, or alternatively for use instead of the adhesives, a balloon may be positioned on the electrode lead array. The balloon is filled with air, liquid or a compliant material. When inflated, the balloon stabilizes the lead with respect to the spinal cord and holds the lead in place. An elastic aspect of the balloon serves as an internal contained relief valve to limit the pressure the balloon may place on the surrounding tissues when the epidural space is constrained.

The present application is a Continuation-in-Part of U.S. applicationSer. No. 10/155,146, filed May 24, 2002; which claims the benefit ofU.S. Provisional Application Ser. No. 60/294,283, filed May 29, 2001,which applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a neural stimulation systems, e.g., aspinal cord stimulation system. More particularly, the invention relatesto neural stimulation leads that include lead fixation means, i.e., waysto assure that the lead, once implanted, does not move away from itsdesired implant location.

Spinal cord stimulation (SCS) is a well accepted clinical method forreducing pain in certain populations of patients. SCS systems typicallyinclude an implanted pulse generator, lead wires, and electrodesconnected to the lead wires. The pulse generator generates electricalpulses that are delivered to the dorsal column fibers within the spinalcord through the electrodes which are implanted along the dura of thespinal cord. In a typical situation, the attached lead wires exit thespinal cord and are tunneled around the torso of the patient to asub-cutaneous pocket where the pulse generator is implanted.

When an electrical pulse, or sequence of pulses, is applied to aselected electrode, or combination of electrodes, the patient typicallyexperiences a “paresthesia” (usually manifest as a mild tinglingsensation) that is therapeutic, i.e., that relieves the pain, or otherdiscomfort, the patient is experiencing, or that otherwise aids thepatient in some useful way.

Spinal cord and other stimulation systems are known in the art. Forexample, in U.S. Pat. No. 3,646,940, there is disclosed an implantableelectronic stimulator that provides timed sequenced electrical impulsesto a plurality of electrodes so that only one electrode has a voltageapplied to it at any given time. Thus, the electrical stimuli providedby the apparatus taught in the '940 patent comprise sequential, ornon-overlapping, stimuli.

In U.S. Pat. No. 3,724,467, an electrode implant is disclosed for theneuro-stimulation of the spinal cord. A relatively thin and flexiblestrip of physiologically inert plastic is provided with a plurality ofelectrodes formed thereon. The electrodes are connected by leads to anRF receiver, which is also implanted, and which is controlled by anexternal controller. The implanted RF receiver has no power storagemeans, and is coupled to the external controller in order forneuro-stimulation to occur.

In U.S. Pat. No. 3,822,708, another type of electrical spinal cordstimulating device is shown. The device has five aligned electrodeswhich are positioned longitudinally on the spinal cord and transverselyto the nerves entering the spinal cord. Current pulses applied to theelectrodes are said to block sensed intractable pain, while allowingpassage of other sensations. The stimulation pulses applied to theelectrodes are approximately 250 microseconds in width with a repetitionrate of from 5 to 200 pulses per second. A patient-operable switchallows the patient to change which electrodes are activated, i.e., whichelectrodes receive the current stimulus, so that the area between theactivated electrodes on the spinal cord can be adjusted, as required, tobetter block the pain.

Other representative patents that show spinal cord stimulation systemsor electrodes include U.S. Pat. Nos. 4,338,945; 4,379,462; 4,519,403;5,121,754; 5,417,719 and 5,501,703, incorporated herein by reference.

The '403 patent teaches a balloon lead and inflator. However, the '403patent does not teach the use of a safety valve to release pressure thatmight build up, or otherwise be present, when such lead is used.

U.S. Pat. No. 5,733,322, also incorporated herein by reference,discloses a positive fixation percutaneous epidural neurostimulationlead that utilizes an extension that extends distally beyond the mostdistal electrode. The extension is held in place by contact with boththe dura and spinal canal wall so that lateral lead migration of theelectrodes is minimized. Other electrode fixation techniques are taught,e.g., in U.S. Pat. No. 4,418,697, which describes an adhesive (putty) tofixate electrodes to the skin; and in U.S. Pat. No. 4,282,886, whichdescribes an adhesive adapted to attach an electrode to the epicardium.Both the '697 and the '886 patents are likewise incorporated herein byreference.

Disadvantageously, when a neural stimulation lead chronically ortemporarily moves, the ramifications to the patient are multifold. Forexample, an SCS lead that moves up, down or rotates to the side of thespinal cord can result in therapy no longer being adequate to attain thedesired paresthesia, thereby rendering the SCS system incapable ofperforming its intended function. On a temporary basis, the lead canmove, which movement may thereafter require patient adjustment of thestimulation energy, e.g., to reduce the stimulation output or increasethe stimulation output, and in some instances such adjustment of thestimulation energy may not be possible, thereby again rendering the SCSsystem ineffective for its intended purpose.

Thus, it is seen that maintaining the correct lead position is critical,and an undesirable movement of the lead can render the SCS, or otherneural stimulation system, ineffective and useless. Moreover, as thecorrect lead position is maintained, appropriate safeguards should existto prevent excessive compression of the spinal cord. What is needed aremechanisms built into the lead design that: (1) acutely fixate the leadto its desired location, e.g., to the dura in the case of an SCS system,to thereby allow scare maturation to occur (which scare maturation willthereafter permanently maintain the lead in its desired location); or(2) permanently fixate the lead in its desired location from the onsetof implantation; and (3) limit compression on the spinal cord.

SUMMARY OF THE INVENTION

The teachings of the present disclosure address the above and otherneeds by providing an implantable neural lead having an electrode arrayat or near its distal end that prevents undesirable movement of theelectrode array from its initial implant location by filling the spacethat surrounds the lead into which the lead could otherwise move, and/orthat adheres, i.e., “glues”, the electrode array to its desired implantlocation.

In the case of an SCS lead, movement of the lead array is predominatelycaused due to the geometry of the epidural space. That is, the epiduralspace allows the spinal cord to independently move with respect to thevertebra, disks and ligaments which comprise the structural support ofthe spine. In one embodiment of the present disclosure, a firstinjectable material that adheres to the dura is injected into the duraspace to mechanically position the electrode array with respect to thespinal cord. This first adhering material is introduced through thelumen of the lead array. An orifice to the lumen, which may be markedwith a radio opaque marker, is located on the side of the lead where theattachment is to occur so that the adhering material is emitted from thelead tangential to the lead body at the level of the stimulatingelectrodes. By way of example, the first adhering material may beselected from the group that includes cyanoacrylate, fibrin,reconstituted collagen, polyethylene glycol, and polyacrylamide. Otherexamples of adhering materials that may be used include aldehyde (e.g.glutaraldehyde or formaldehyde), cross-linked natural proteins (e.g.collagen or albumin), chitosan adhesives (mussel glue), and photocurableadhesives (e.g., silicones, acrylates, polysaccharides, proteins, etc.).

In a second embodiment, used in conjunction with or as an alternative tothe first embodiment, a balloon is positioned on the electrode leadarray. Such balloon runs along the axis of the lead at the stimulatingelectrode level and encompasses a significant portion, e.g., 180degrees, of the arc when a cross section of the lead is viewed. Theballoon is filled with air, liquid or a compliant material. Wheninflated, the balloon stabilizes the lead with respect to the spinalcord. The pressure of the balloon is monitored or otherwise controlledduring the filling process in order to determine at what point thefilling process should be discontinued. The balloon may be segmentedinto several balloon compartments, each having different dilated balloondiameters to account for different geometry between and within a givenpatient. An elastic aspect of the balloon serves as an internalcontained relief valve to limit the pressure the balloon may place onthe surrounding tissues when the epidural space is constrained.

In accordance with one aspect of the present disclosure, an implantablelead is thus provided that is fixed to its desired implant location.

In accordance with another aspect of the present disclosure, a lumenwithin the lead, used to allow a removable stylet to help place andposition an electrode array at or near a distal end of the lead duringthe implant process, may also be used as the channel through which thefirst adhering material is dispensed. Such dispensing may occur eitherthrough insertion of a cannula within the lumen (followed by dispensingthe first adhering material within the cannula) or direct injection ofthe first adhering material into the lumen. Additionally, in oneembodiment such channel further serves as a fluid inlet (where “fluid”is used here in its broad sense to mean either a liquid or a gas)through which a balloon formed in the lead near or at the location ofthe electrode array may be inflated to a desired size and/or pressure.In another embodiment, a separate fluid channel may be formed throughthe lead body through which the balloon may be inflated. In yet anotherembodiment, the first adhering material also functions as the fluid thatinflates the balloon(s).

In accordance with still a further aspect of the present disclosure, thelead includes an implanted pressure release mechanism to ensure thatthere is not excessive compression placed on the spinal cord by theimplantable lead.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the teachings ofthe present disclosure will be more apparent from the following moreparticular description thereof, presented in conjunction with thefollowing drawings wherein:

FIG. 1 illustrates a representative spinal cord stimulation systemimplanted in a patient;

FIG. 2 is a sectional view that depicts the electrode array as taught bythe present disclosure implanted adjacent the spine;

FIG. 3 is a first side view of the electrode array as taught by thepresent disclosure, with the balloon inflated, as viewed while lookingat the back side of the array, i.e., that side opposite from the orificethrough which an adhering material may be dispensed;

FIG. 3A is a sectional view of the array shown in FIG. 3 taken along theline 3A-3A, and illustrates the balloon in both an inflated and deflatedcondition;

FIG. 3B is a sectional view of the array shown in FIG. 3 taken along theline 3B-3B, and illustrates the balloon in an inflated condition;

FIGS. 4 and 4A depict an alternative embodiment wherein a series of sidelobe balloons are employed with an electrode array;

FIGS. 5 and 5A similarly show an alternative embodiment wherein a seriesof lateral stabilizing balloons are employed with the electrode array;and

FIG. 6 shows another alternative embodiment wherein a spongy, flexibleor compressive portion is employed with an electrode array.

Corresponding reference characters indicate corresponding componentsthroughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best mode presently contemplated forcarrying out the invention. This description is not to be taken in alimiting sense, but is made merely for the purpose of describing thegeneral principles of the invention. The scope of the invention shouldbe determined with reference to the claims.

At the outset, it should be noted that the teachings of the presentdisclosure are directed to the fixation of implantable leads, such asneural stimulation leads or cardiac leads, and more particularly to thefixation of electrodes, or electrode arrays, attached to neuralstimulation leads or cardiac leads so that such electrodes, or electrodearrays, remain in a desired position relative to the tissue that is tobe stimulated. For purposes of the present disclosure, the terms “lead”and “electrode” and “electrode array” may thus be used interchangeably,unless the context clearly indicates otherwise. That is, while thenarrow purpose of the present discloure is to fix the electrodesrelative to the tissue to be stimulated, in describing such purposeother terminology may be used, such as fixing the lead, or fixing theelectrode array.

It should further be noted that the principles and teachings of thepresent disclosure may be used with any kind of neural stimulation lead,or cardiac lead, particularly those that are implanted within a tissuecavity (the presence of which cavity allows undesirable movement of thelead). Thus, while the present disclosure will be described in terms ofa spinal cord stimulation (SCS) lead adapted for implantation in theepidural space next to the spine, it is to be understood that suchdescription is intended to be only exemplary and not limiting. The scopeof the present disclosure is determined by the claims.

Turning first to FIG. 1, there is shown a representative SCS system 10implanted in a patient 11. The SCS system 10 is used typically to treatchronic pain by applying electrical stimulation pulses to selectedlocations along the spine. The SCS system 10 includes an ImplantablePulse Generator (IPG) 12 that generates the electrical stimulationpulses used for stimulation. An electrode array 14 at or near the distalend of an implanted stimulation lead 15 is inserted into the epiduralspace next to the spinal cord 18. As required, depending upon thelocation where the IPG 12 is implanted, a lead extension 16 may be usedto connect the lead 15 (and hence the electrode array 14) to the IPG.The electrical stimulation provided by the IPG 12, when properlyperformed, has the effect of blocking sensed pain while not interferingwith other nerve functions. The present disclosure relates to theelectrode array 14 and the manner used to fix the location of theelectrode array 14 relative to the spinal cord 18.

FIG. 2 schematically illustrates a sectional view of the epidural space20 adjacent the spinal cord 18 into which the implantable lead 15, andmore particularly the electrode array 14 at the distal end of the lead15, of the present disclosure is implanted. As seen in FIG. 2, theelectrode array 14 typically includes a multiplicity of spaced-apartelectrode contacts 24. Such electrode contacts 24 may reside along oneside of the array 14, or may be bands that encircle a body 15A of thelead 15. Each electrode contact 24 is electrically connected to arespective wire 26 that is embedded, or otherwise located within, thebody 15A of the lead 15. For the example shown in FIG. 2, the wires 26are helically wound, thereby allowing the lead 15 to readily flex andbend. The inside of the helically wound wires 26 defines a lumen 22 thatpasses longitudinally through the body of the lead. A proximal end ofthe wires 26 (not shown in FIG. 2) connects to the IPG 12 eitherdirectly or through an extension lead 16 (FIG. 1). It is to beunderstood that a lead having helically-wound wires 26 thereinrepresents only one way in which an implantable neural stimulation leadmay be formed. Any method known in the art, or yet to be developed inthe art, for electrically connecting an electrode contact 24 to animplantable pulse generator may be used with the present disclosure.

The body 15A of the lead 15 may be made from any suitable biocompatiblematerial, such as silicone or Silastic or other compliant material, asis known in the art, or as will yet be developed in the art. The body15A of the lead 15 may also be referred to as a flexible carrier onwhich the spaced-apart electrode contacts 24 are carried.

At least one orifice 27 is formed in the body 15A of the array 14 nearthe electrode contacts 24. The location of the orifice 27 along the leadbody 15A may be marked with a radio opaque marker 29. It is through thisorifice 27 that a first adhering material 30, e.g., an adhesive, may bedispensed through the lumen 22 of the lead 15 to the area where theelectrode array 14 is to be attached, e.g., adhered or glued, to thespinal cord 18. (This adhering material 30 is represented in FIG. 2 byclosely spaced small dots.)

Rather than dispensing the adhesive through a lumen 22 that passesthrough the lead body, it is also possible, in accordance with analternative embodiment of the teachings of the present disclosure, toprovide a cannula, or similar tubing, that passes along one side of thelead body, e.g., parallel to the flexible carrier, with an opening ororifice near the electrode contacts.

It should be noted that the adhesive may have properties that cause itto adhere to the body tissue and to (1) the electrode contacts 24, or(2) insulative material separating the electrode contacts, or (3) boththe electrode contacts 24 and the insulative materials separating theelectrode contacts. In some embodiments of an implantable lead, in theregion near the electrode contacts 24, the electrode contacts areseparated by insulative material, which is non-conductive. Thus, forpurposes of maintaining or holding the position of the electrodecontacts near or against the tissue to be stimulated, it matters littlewhether the adhesive bonds with the electrode contacts, and/or with theinsulative material that separates or insulates the electrode contactsfrom each other, or other insulative material, in the vicinity of theelectrode contacts. However, as discussed below, it is generallypreferable that the adhesive not bond with a compliant material, i.e.,that it not bond with silicone or other material from which the leadbody 15A is made. Thus, in most instances, except when an insulative orother material is used near the electrodes that is different fromsilicone, or other material from which the lead body is made, theadhesive bonds with the electrode contacts and with the surroundingtissue.

The adhering material 30 has properties that allow it to be injectedthrough the lumen 22 and orifice 27 of the lead 15. Additionally, thematerial 30 should have properties that cause it to adhere to the dura19 (an outer layer that surrounds the spinal cord 18) and the electrodecontacts 24, but which do not cause it to adhere to the dura spacelining or a compliant material (e.g., the silicone or other materialfrom which the lead body 15A is made). By way of example, the firstadhering material 30 may be selected from the group that includescyanoacrylate, fibrin, reconstituted collagen, polyethylene glycol, andpolyacrylamide. Other examples of adhering materials that may be usedinclude aldehyde (e.g. glutaraldehyde or formaldehyde), cross-linkednatural proteins (e.g. collagen or albumin), chitosan adhesives (musselglue), and photocurable adhesives (e.g., silicones, acrylates,polysaccharides, proteins, etc.).

It is thus seen that the teachings of the present disclosure addressesthe use of an adhesive to fix the actual electrode itself to the tissue.On exemplary embodiment contemplates injecting the adhesive through thelumen 22 and orifice 27 of the lead 15. However, other techniques mayalso be used, particularly for other types of lead and electrodeconfigurations. For example, the adhesive may be placed prior to, duringor after the implantation of the electrode(s). The adhesive isformulated to be gentle to the tissue, but assures that the electrode(s)remain in the desired proper location and orientation because thefixation is on the electrode itself. The adhesive may be used inconjunction with traditional methods, e.g., fixation at a distance. Theadhesive may also be made soft or hard, permanent or temporary, and canbe made to be biocompatible. The adhesive may be synthetic, e.g.,cyanoacrylate, or it may be a substance that is natural to the body,e.g., fibrin glue.

Returning to FIG. 2, it is further seen in FIG. 2, the electrode array14 also includes a balloon 40 that, when inflated, fills the remainingepidural space 20 surrounding the electrode array 14 and lead 15.Further details relating to the balloon 40 are discussed below inconjunction with the description of FIGS. 3-5. While both the balloon 40and adhesive 30 are illustrated as being used in connection with thesame lead 15 in FIG. 2, such conjunctive use is only exemplary. In someinstances, only the adhesive 30 need be used to fix the electrodecontacts to a desired location. In other instances, only the balloon 40need be used.

Typically, after removal of the stylet from the lumen 22, the adheringmaterial 30 is injected into the lumen 22. As it is injected, it fillsthe distal end of the lumen first, and then exits out the orifice 27into the space adjacent the spinal cord 18 where the adhesion occursbetween the dura 19 and electrode contacts 24. Because the volume of thelumen at the distal end of the lead up to the location of the orifice 27is known, or can be readily calculated (i.e., the orifice 27 is a knowndistance D from the tip of the electrode array 14, and the distance d1from the tip to the beginning of the lumen 22 is also known or can bereadily estimated; thus, the approximate volume of the lumen 22 up tothe location of the orifice 27 can be determined), a desired amount(volume) of material 30 to be injected through the lumen 22 can bedetermined.

After the proper amount, e.g., volume, of adhesive or other adheringmaterial 30 has been injected into the lumen 22, a second material,e.g., a gas, such as air, or a liquid which does not mix with the firstmaterial 30, may also be injected into the lumen 22, forcing the firstadhering material 30 to the distal end of the lumen, and through thefirst orifice 27, as desired. This second material may then pass througha second orifice 28 in order to inflate the balloon 40 to a desiredpressure. Alternatively, where the first material 30 does not readilyadhere to compliant materials, such as the materials from which the body15A of the lead 15 is made, and from which the balloon 40 is made, thefirst material 30 may, in addition to being injected through the orifice27 in order to adhere the dura 19 to the electrode contacts 24, also beused as the substance that inflates the balloon 40 to a desiredpressure. As a still further means of inflating the balloon, the balloon40 may be inflated to a desired pressure and/or volume by injecting aninflating material, e.g., a saline solution, through a separate channel25 apart from the lumen 22, as shown in FIG. 3B, discussed below.

Turning next to FIGS. 3, 3A and 3B, further details associated with oneembodiment of the electrode array 14 of the present disclosure areillustrated. FIG. 3 is a first side view of the electrode array 14, withthe balloon 40 inflated, as viewed while looking at the back side of thearray, i.e., that side opposite from the orifice 27 through which theadhering material 30 is dispensed. FIG. 3A is a sectional view of thearray shown in FIG. 3 taken along the line 3A-3A, and illustrates theballoon 40 in both an inflated and deflated condition. FIG. 3B is asectional view of the array shown in FIG. 3 taken along the line 3B-3B,and illustrates the balloon 40 in an inflated condition. As seen inFIGS. 3, 3A and 3B, the orifice 27 through which the adhering materialis dispensed is located near the electrode contacts 24. The balloon 40inflates around the portion of the electrode array 14 where theelectrode contacts 24 are located. As seen best in the cross-sectionalview of the lead 15 shown in FIG. 3A, the balloon 40 encircles the lead14 over an angle α. The angle α will typically range from about 20 to180 degrees, but may, in some embodiments, range from about 20 to 270degrees.

For the exemplary embodiment shown in FIGS. 3, 3A and 3B, the balloon 40is inflated through a channel 25 and orifice 28′ that is separate fromthe lead lumen 22 and orifice 27. When the balloon 40 is inflated, somemeans for monitoring the injected material pressure so as to determinean appropriate point at which the inflation should terminate may beused. Such means may be simply injecting a known volume of inflatingfluid. Alternatively, a pressure gauge may be used in conjunction withthe inflating process so that the pressure of the inflating fluid can beaccurately measured.

Also, for the exemplary embodiment shown in FIGS. 3, 3A and 3B, theballoon 40 includes sections 42 that have different elastic propertiesthan the main balloon portion, e.g., are made so as to have a thickerwall than the main balloon portion. Thus, these balloon sections 42require more pressure to inflate. As such, the balloon portions 42function as an internal contained relief valve to limit the pressure theballoon 40 may place on the surrounding tissue when the epidural spaceis constrained (which may occur, for example, when the patient bends hisback or spine). Limiting the pressure that the balloon 40 can impart tothe surrounding tissue through use of such internal contained reliefvalues 42 helps assure that the patient will not experience any unduediscomfort as he or she moves about. In this way, excessive compressionon the spinal cord is avoided.

Next, with reference to FIGS. 4 and 4A, an alternative exemplaryembodiment is illustrated wherein a sequence of lobe balloons 41 areemployed with an electrode array 14. Such embodiment includes a sequenceof three lobe balloons 41 for each electrode contact 14. Such number oflobe balloons in each sequence is only exemplary. Further, while theembodiment shown in FIGS. 4 and 4A has one sequence of lobe balloonsassociated with each electrode contact, it is also possible to have asequence of lobe balloons associated with only selected electrodecontacts, e.g., a most distal electrode contact, a most proximalelectrode contact, and/or a middle electrode contact. The lobe balloons41 are inflated through the longitudinal lumen 22. When inflated, thelobe balloons 41 engage the tissue surrounding the distal end of theimplanted neural lead 15 and secure the electrode array 14 to the tissuewithin which it is implanted. Each lobe balloon 41 includes an internalpressure relief portion 43.

Further, with reference to FIGS. 5 and 5A, yet another exemplaryembodiment is depicted wherein a series of lateral stabilizing balloons40′ are employed with the electrode array 14. Each stabilizing balloon40′ includes an internal pressure relief portion 42′. The number oflateral stabilizing balloons 40′ will typically be at least two, andcould be as many as four or five, or more, depending upon the length ofthe electrode array 14. The stabilizing balloons 40′ are inflatedthrough the longitudinal lumen 22. When inflated, the stabilizingballoons 40′ engage the tissue surrounding the distal end of theimplanted neural lead 15 and secure the electrode array 14 to the tissuewithin which it is implanted.

In addition to the internal pressure relief portions 42 (FIGS. 3A, 3B),42′ (FIG. 5) and 43 (FIG. 4), which form part of the main balloonportion but with a thicker wall, other types of pressure reliefmechanisms may be employed. For example, other highly compliantexpandable positioning systems, such as foam, sponge or other latticematerials may also be employed. Indeed, the teachings of the presentdisclosure contemplates any pressure relief mechanism built into thelead that ensures excessive compression of the spine is avoided. Thus,as illustrated in FIG. 6, a spongy, flexible and/or compressible portion50 is formed on the lead 15, opposite the electrodes 24. While thespongy, flexible and/or compressible portion 50 may be an elongatemember, as shown in FIG. 6, it should also be understood that suchportion(s) 50 may be at the same location and using the same or similarpatterns, as are employed by the balloon portions previously described.

The portion 50 is made from a silastic spongy material that is bothflexible and compressible. A suitable flexible and compressible materialthat may be used for the portion 50 is, e.g., polyurethane, orequivalents. The portion 50 may be fabricated as: (1) an open cellmaterial that is collapsed through application of a vacuum on the lumenand/or implant insertion, with the vacuum being removed after insertion,allowing the open cell material to open from its collapsed state; or (2)a balloon filled with a foam, which foam is flexible and compressible.It is to be emphasized that any material that is compatible with bodytissue and sufficiently flexible and compressible may be used for theportion 50, including materials that may not yet be developed.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations could be made thereto by those skilled in the art withoutdeparting from the scope of the invention set forth in the claims.

1. An implantable lead comprising: a lead body; a lumen passinglongitudinally through or along side the lead body; at least oneelectrode contact carried on the lead body at or near a distal end ofthe lead; means for making electrical contact with the at least oneelectrode contact from a proximal end of the lead; a first orifice nearthe at least one electrode contact, wherein the first orifice providesfluid communication between the lumen and an exterior of the lead; afirst adhering material injectable through said lumen and first orificeto make contact with, and adhere said at least one electrode contact to,surrounding tissue; an inflatable balloon integral with the lead bodyand opposite the first orifice, said inflatable balloon including aninternal pressure relief portion; and a second orifice that fluidlyconnects the lumen with the inflatable balloon, wherein an inflatingmaterial may be injected into the balloon to inflate it through thelumen and second orifice, wherein said first adhering material and saidinflating material comprise the same material.
 2. The implantable leadof claim 1 wherein said first adhering material is selected from thegroup comprising cyanoacrylate, fibrin, reconstituted collagen,polyethylene glycol, polyacrylamide, aldehyde, cross-linked naturalproteins, chitosan adhesives, and photocurable adhesives.
 3. Theimplantable lead of claim 2 wherein the at least one electrode contactcomprises a plurality of spaced-apart electrode contacts, and whereinthe implantable lead is adapted to connect to a spinal cord stimulationsystem.
 4. The implantable lead of claim 1 further including a secondchannel through the lead body that is separate and apart from the lumen,wherein said second channel is adapted to direct the inflating materialinto the balloon.
 5. The implantable lead of claim 1 wherein the firstadhering material is an adhesive.
 6. The implantable lead of claim 5wherein the adhesive is made hard.
 7. The implantable lead of claim 5wherein the adhesive is made soft.
 8. The implantable lead of claim 5wherein the adhesive is permanent.
 9. The implantable lead of claim 5wherein the adhesive is temporary.
 10. The implantable lead of claim 5wherein the adhesive is made from a synthetic material.
 11. Theimplantable lead of claim 5 wherein the adhesive is made from asubstance that is natural to the body.
 12. The implantable lead of claim5 wherein the adhesive is biocompatible and formulated to be gentle tobody tissue.
 13. The implantable lead of claim 1 wherein said firstadhering material is selected from the group comprising cross-linkednatural proteins and chitosan adhesives.
 14. An implantable leadcomprising: a lead body; a lumen passing longitudinally through or alongside the lead body; at least one electrode contact carried on the leadbody at or near a distal end of the lead; means for making electricalcontact with the at least one electrode contact from a proximal end ofthe lead; a first orifice near the at least one electrode contact,wherein the first orifice provides fluid communication between the lumenand an exterior of the lead; a first adhering material injectablethrough said lumen and first orifice to make contact with, and adheresaid at least one electrode contact to, surrounding tissue; aninflatable balloon integral with the lead body and opposite the firstorifice, said inflatable balloon including an internal pressure reliefportion, wherein the inflatable balloon includes an inflatable firstportion and an inflatable second portion, wherein the second portioncomprises the internal pressure relief portion, and wherein the secondportion has different elasticity properties than the first portion suchthat more pressure is required to begin inflating the second portionthan is required to begin inflating the first portion, wherein thesecond portion of the inflatable balloon provides an internal containedrelief valve that limits the pressure in the first balloon portion. 15.The implantable lead of claim 14 wherein the inflatable balloon coversan area at a distal end of said lead body that, when the lead body isviewed in cross section, extends over an angle α of between 20 to 270degrees.
 16. The implantable lead of claim 14 further including a seriesof inflatable lateral stabilizing balloons spaced apart along a distalportion of the lead body.
 17. The implantable lead of claim 14 whereinsaid inflatable balloon comprises a sequence of inflatable lobesassociated with selected electrode contacts.
 18. The implantable lead ofclaim 17 wherein the number of inflatable lobes in each sequence ofinflatable lobes is three.
 19. The implantable lead of claim 14 furtherincluding a second orifice that fluidly connects the lumen with theinflatable balloon, wherein an inflating material may be injected intothe balloon to inflate it through the lumen and second orifice.
 20. Theimplantable lead of claim 19 wherein said first adhering material andsaid inflating material comprise the same material.
 21. The implantablelead of claim 14 where the inflatable first and second portions of theinflatable balloon have inflatable walls made from the same material,and wherein, prior to inflation, the inflatable walls of the inflatablesecond portion are thicker than the inflatable walls of the inflatablefirst portion.
 22. An implantable lead comprising: a lead body; a lumenpassing longitudinally through or along side the lead body; at least oneelectrode contact carried on the lead body at or near a distal end ofthe lead; means for making electrical contact with the at least oneelectrode contact from a proximal end of the lead; a first orifice nearthe at least one electrode contact, wherein the first orifice providesfluid communication between the lumen and an exterior of the lead; afirst adhering material injectable through said lumen and first orificeto make contact with, and adhere said at least one electrode contact to,surrounding tissue; an inflatable balloon integral with the lead bodyand opposite the first orifice, said inflatable balloon including aninternal pressure relief portion, wherein the inflatable balloonincludes an inflatable first portion and an inflatable second portion,wherein the first and second portions of the inflatable balloon haveinflatable walls made from a same material, and wherein, prior toinflation, the inflatable walls of the second portion are thicker thanthe inflatable walls of the first portion.
 23. The implantable lead ofclaim 22 wherein the inflatable balloon covers an area at a distal endof said lead body that, when the lead body is viewed in cross section,extends over an angle α of between 20 to 270 degrees.
 24. Theimplantable lead of claim 22 further including a series of inflatablelateral stabilizing balloons spaced apart along a distal portion of thelead body.
 25. The implantable lead of claim 22 wherein said inflatableballoon comprises a sequence of inflatable lobes associated withselected electrode contacts.
 26. The implantable lead of claim 25wherein the number of inflatable lobes in each sequence of inflatablelobes is three.
 27. The implantable lead of claim 22 further including asecond orifice that fluidly connects the lumen with the inflatableballoon, wherein an inflating material may be injected into the balloonto inflate it through the lumen and second orifice.